An ink jet printer prints a printing object provided in a form of a flexible paper sheet, a film or something in a roll.
When using the ink jet printer, a printing object is inserted into an ink jet printer, and an ink jet printer starts printing a printing object as a printer head horizontally reciprocates in a direction perpendicular to a transferring direction of a printing object when a transfer roller transfers a printing object.
The ink jet technology applied to such ink jet printer is widely applied to a home/office small size printer as well as an industrial big size printer. In recent years, an industrial ink jet printer using a UV ink is widely used in industries. The industrial ink jet printer is basically designed to print a flexible printing object such as paper sheets, woven materials, etc. as well as a rigid and large-sized printing object such as a wooden plate, a metallic plate, a glass plate, etc.
A representative of such industrial ink jet printers is disclosed in Korean patent registration number 10-0434825 entitled “Flat bed type ink jet printer”.
The above flat type ink jet printer is designed to print a printing object which is rigid, heavy or thick. The flat type ink jet printer comprises a bed with an air passage in its interior and an air suction part formed at its upper surface, a fixing support part integrally fixed at the bed, thus supporting the bed, an air suction part connected with the air passage for discharging or sucking the air, a head bar engaged to the bed for thereby helping the head horizontally in a horizontal direction, and a transfer part for helping the head bar to move horizontally in a direction vertical to the bed.
The conventional ink jet printer is basically directed to printing with the aid of an operation of a printer head while a printing object such as a paper sheet or film is being transferred by means of the transfer roller, but since the flat type ink jet printer is directed to printing a printing object such as a wooden plate, a metallic plate, a glass plate, etc. which is heavy or big, the printer head prints while moving along the whole portions of the bed in a state that a printing object is placed on the bed.
The conventional flat type ink jet printer uses a vacuum suction force so as to stably fix a printing object on a bed.
A plurality of air suction ports are formed at an upper surface of the bed and the interior of the bed has a certain space for fixedly sucking a printing object with the aid of a suction force. The conventional flat type ink jet printer is formed in one space structure without having a support pole for supporting the bed while efficiently discharging the air from the air suction ports to the air suction part.
The conventional ink jet printer has the following problems.
In the conventional flat type ink jet printer, since a vacuum suction force should be uniformly applied to the entire surfaces of a bed on which a printing object is placed, when a printing object is small in size, an external air might be inputted via some air suction ports on which the printing object does not cover.
So, a larger vacuum suction force is needed so as to fixedly suck a printing object, which leads to increasing power consumption. An over load might be needed to a vacuum suction device, which results in a problem in the system. A lot of noises occur due to a high performance vacuum suction operation.
Since a larger space is provided in the interior of the bed, the conventional flat type ink jet printer is formed without a space in which any poles are not provided so as to suck an inner air in the entire portions of the bed.
In the above construction, when a heavier printing object is placed on the bed, the upper surface of the bed might be bent or broken, so it might be needed to replace the entire parts of the system.
In order to improve the above problems, there is provided a certain means for preventing the bending of the upper surface by adjusting the thickness of an upper surface of the bed, but since the bed is generally made of a little expensive material for obtaining a desired flatness of an upper surface, the manufacture of the conventional flat type ink jet printer costs a lot, which results in a higher sale price, so a user must have pay more money which gives the user a financial problem.
The conventional bed is not equipped with any detection means or control means for checking a vacuum suction force depending on the weight, thickness and dimension of a printing object, the same suction forces are always applied irrespective of the weight and dimension of a printing object placed on the bed.
When a relatively thin and light printing object is placed on the bed, since there is not any measure for checking the above state, a higher vacuum suction force is applied. In this case, a certain dent might be formed on the surface of a printing object due to a strong suction force by means of an air suction part or the surface might be bent, which prevents a proper printing. When a printing is performed without noticing the above problem, the printing does not occur at the problematic surface, so all the finished printing objects might be destroyed, causing a lot of financial losses.
In the conventional art, a worker is needed to adjust a vacuum suction force in a manual method by adjusting a valve depending on the thickness, weight, material or something of a printing object, which leads to very bad operation efficiency of the ink jet printer, causing a lot of economical loses.